Answer: The only graph that shows a proportional relationship is the line that crosses the origin point (0,0).
Explanation
The other graphs are linear functions but not not proportional relationships.
The general form of a proportional relationship is y = kx, where k is the proportionality constant. So, for x = 0 you will always obtain y = 0.
The general form of a linear relationshio is y = kx + b, being b the y-intercept, so if the y-intercept is not 0, it is not a proportional relationship. That is what happens with the other three graphs.
